1. Field of the Invention
The present invention relates to a projection optical system that uses a refractive optical system and a reflective optical system, and which forms, on a screen, an image of an image displayed on an image display device, and also to a projection-type display apparatus including the projection optical system.
2. Description of the Related Art
As a projection-type display apparatus including a projection optical system that uses a refractive optical system and a reflective optical system, and which forms, on a screen, an image of an image displayed on an image display device, apparatuses disclosed in Japanese Unexamined Patent Publication No. 2007-323047 (Patent Document 1), Japanese Unexamined Patent Publication No. 2007-334052 (Patent Document 2), Specification of Japanese Patent No. 4731808 (Patent Document 3) and Specification of Japanese Patent No. 4889289 (Patent Document 4) are known.